Fix FromPixels type checker to avoid error in worker

[shaoboyan]

TFJS is possible running in worker, which doesn't have
ability to access DOM elements.

FromPixels op in tfjs webgpu backend type check
doesn't consider this scene. It will break the whole
program even if user provided correct input params.

Fix this by checking whether DOM is available.

Bug #5467

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This change is 

[shaoboyan]

@lina128 ,
Hi, Na,
I've tried to run the worker_test here(https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts) in webgpu backend. But I've got an error that it cannot load the script from location.origin + '/base/tfjs/tfjs-core/tf-core.min.js' (https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts#L29).
Do you know how to fix this error?

[shaoboyan]

@qjia7 Also cc jiajia

[qjia7]

LGTM with a nit.
@lina128 take another look, thanks.

[lina128]

LGTM

Reviewable status: complete! 2 of 1 approvals obtained (waiting on @qjia7)

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tfjs-backend-webgpu/src/kernels/FromPixels.ts, line 65 at r1 (raw file):

Previously, qjia7 (Jiajia Qin) wrote…

nit: Maybe this checking is not needed since we have done it in the upper level ( tfjs-core

tfjs/tfjs-core/src/ops/browser.ts

Line 96 in 38f8462

throw new Error(

)

+1

[lina128]

@lina128 ,
Hi, Na,
I've tried to run the worker_test here(https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts) in webgpu backend. But I've got an error that it cannot load the script from location.origin + '/base/tfjs/tfjs-core/tf-core.min.js' (https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts#L29).
Do you know how to fix this error?

Hi @shaoboyan, to run the worker test, you need to have some additional karma setup, like the one in core: https://github.com/tensorflow/tfjs/blob/master/tfjs-core/karma.conf.js#L63-L65

[shaoboyan]

@qjia7 Done.

[qjia7]

@lina128 ,
Hi, Na,
I've tried to run the worker_test here(https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts) in webgpu backend. But I've got an error that it cannot load the script from location.origin + '/base/tfjs/tfjs-core/tf-core.min.js' (https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/worker_test.ts#L29).
Do you know how to fix this error?

Hi @shaoboyan, to run the worker test, you need to have some additional karma setup, like the one in core: https://github.com/tensorflow/tfjs/blob/master/tfjs-core/karma.conf.js#L63-L65

@shaoboyan Please follow up the worker test in a separate PR. Thanks.